In the Forward Tool, is my understanding correct that excitation is provided as input to the muscles, and then each parameter is calculated through the muscle model and the skeletal model as shown in the attached image? Additionally, in the arm26.osim model, unless I manually add elements such as "C...

Thank you, Mr. Uchida, for your numerous advices. I will consider the method again.

Thank you for your reply, Mr. Uchida. Indeed I was running the integrator with a fixed time step size. If I make this a variable time step size, might the numerical calculation work better, in which case it would automatically be even finer than the time step size I had set? Also, I am using a fixed...

We are currently using python to simulate the model. -The model I am using is "arm26.osim". -I am controlling the elbow joint angle by giving excitation as input to the model's biceps brachii muscle (BIClong,BICshort). -It seems that the internal numerical calculation of the state variables of the m...

In opensim 4.4, simulations were performed on the "arm26.osim" model using python. The elbow joint angles were controlled by inputting excitation to the "BIClong" and "BICshort" muscles. As shown in the figure, when a step input was applied to each muscle, the elbow joint angle suddenly increased sh...

Hi, Mr Thomas Uchida.
Thank you for your response.
My question has been resolved!

I ran a simulation with the forward dynamics tool and in the results there are negative values for activation. The simulation conditions are as follows The model "arm26" was used. The simulation was performed for 20 seconds. The excitation was entered only for "BIClong" and its value was increased p...

I am currently looking to do a model simulation of FES (Functional Electrical Stimulation) using opensim version 4.4. The model I am using is "arm26.osim". The target motions I want to achieve with FES are flexion and extension of the elbow, and therefore the target muscles are the biceps brachii an...